Police fear that the murder of a former Kremlin spy may have been part of a double killing plot after a second man was taken to hospital last night with radiation poisoning.

The Anti-Terror Group is examining whether the killers of Alexander Litvinenko also tried to poison Mario Scaramella, an Italian security expert who met the Russian exile on the day that he fell ill.

Toxicologists confirmed yesterday that Mr Scaramella had also been contaminated by a “significant” amount of deadly polonium-210. The level leads them to suspect that it was more than he could have ingested from simple physical contact with Litvinenko.

Radiological experts also say that the amount is more than he could have inhaled from being close to Litvinenko had he coughed or sneezed. Cobra, the Government’s emergency planning committee, met after learning of Mr Scaramella’s contamination.

Doctors say it may be several weeks before the Italian academic knows the long-term effects of the contamination and whether he is likely to develop cancer. Mr Scaramella has ingested nothing like the amount that Litvinenko did, which explains why he has not shown the same acute symptoms, but doctors say that there is a longer-term risk of him developing cancer.

One health expert told The Times last night: “There is no known way of getting rid of polonium-210 from the body, so it does cause long-term damage.” Mr Scaramella met the former KGB colonel on November 1 at the Itsu sushi bar in London that the men used as a rendezvous.

The two were critics of the Kremlin and both appeared on a death list drawn up by a group of former KGB agents reportedly behind a number of murders abroad of enemies of President Putin.

Detectives believe that a sizeable team travelled from Russia to smuggle the polonium-210 into Britain and shadow Litvinenko. There is a suspicion that Litvinenko’s mobile telephone was bugged and the surveillance team knew of his meeting with the Italian security expert, who had taken part in a parliamentary investigation in Rome into KGB dirty tricks.

Tests have shown that an adult member of Litvinenko’s family, who was close to him during his illness, was exposed to a very small amount of polonium-210, the Health Protection Agency said last night. Traces of radiation were found on the clothing of the person, believed to be Litvinenko’s wife, Marina. The levels are minute, the agency said, and any risk to health is likely to be very small. Other members of the family are understood to have tested negative.

Police will meet medical experts today to discover whether Mr Scaramella ingested the polonium-210 by accident as it was transferred by his lunch guest or whether he, too, was deliberately poisoned. Only Litvinenko ate lunch. Mr Scaramella had a bottle of water.

The Health Protection Agency said that the amount of poison found in Mr Scaramella was “likely to be of concern to his immediate health”. That Mr Scaramella has yet to show any symptoms does not mean that he was not significantly poisoned. A briefing by the Chief Medical Officer, Sir Liam Donaldson, suggests that it may take up to four weeks for symptoms to show for lower but still deadly doses.

Mr Scaramella had been due to fly back to Italy today but will remain under guard in a London hospital. Police, who questioned him in London on Thursday, are said to have ruled him out as a suspect. The officers who carried out the questioning in West London will now be tested for exposure.

While police are still trying to discover how the poison was administered to Litvinenko, they now believe that it was delivered at the sushi bar.

A post-mortem examination was carried out on Litvinenko yesterday by three pathologists but police say the outcome will not be known for several days.

Police and toxicologists will need to trace Mr Scaramella’s whereabouts during his time in London, and Italian authorities have been advised to do the same. A Cabinet Office spokesman said: “We have officially informed the Italian Government . . . they have the same predicament about airlines that we faced because Mr Scaramella flew out of the country.” Giancarlo Aragona, the Italian Ambassador, said last night: “The health authorities here and in Italy are in contact but no moves have yet been made to check or ground any aircraft.”

Yesterday an hotel where Mr Scaramella is believed to have stayed was sealed off while radiation tests were carried out, but no traces were found at the Ashdown Park Hotel in Wych Cross, East Sussex.

So far 2,655 people have contacted NHS Direct, fearing that they may have been in contact with the substance: 356 have been asked to provide a urine sample for further analysis.

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